Aristotle asserts that man (anthropos) possesses an essential nature. According to Aristotle, man is by nature a "social and political animal" (zoon politikon). What Aristotle means by this is not simply that human beings are naturally gregarious. Rather, in his view, man is an ethical being—one that is destined to live an ethical life. In Aristotle's opinion, individual human beings undergo a process of development over time. They develop and become more mature. At the end of this process, they fully actualize the potential for ethical life that they possessed at the beginning. To live such a life is the telos, that is to say, the final purpose or ultimate goal in life, which Aristotle associates with the notion of what it is to be a human being.
To say that individuals have achieved this end is but another way of saying that they have finally arrived at that state or condition Aristotle refers to as eudaimonia. This term is often translated as happiness but is perhaps better rendered by the term fulfillment or completion. There are two dimensions to ethical life as Aristotle understands it. The first is that an ethical life is a virtuous life, one devoted to the cultivation of the virtues. The discussions of this lie at the heart of Aristotle's Nicomachean Ethics. Indeed, the emphasis that Aristotle places on these virtues has led many contemporary Aristotelians, notably Alasdair MacIntyre, to characterize his views by the label "virtue ethics." The second, which is more directly relevant to political theory, is the emphasis that Aristotle places on the importance of just one of these virtues, justice. For Aristotle, an ethical life is above all else a life of justice. Ethical Life and Justice Aristotle's account of justice in his Nicomachean Ethics has never been bettered and is still in use today. Aristotle distinguishes between justice in general and justice in particular. He explains the meaning of the concept of justice in the latter sense by reference to the notion of equity.
Broadly speaking, for Aristotle, justice in this sense is a matter of treating like cases alike and unlike cases differently. However, this provisional characterization needs qualifying in two ways. First, those whose circumstances are considered to be alike, or who are considered to be equals, must really be so. That is to say, they must be alike in some ethically relevant respect. Second, if it is true that treating unequal differently might in certain circumstances be justified because there is some relevant difference between them, nevertheless, the difference in the treatment must be one of due proportion.
Aristotle goes on to consider two areas in which this view of justice has an application, which he refers to as the spheres of rectification justice and of distributive justice, respectively. In the first of these, it is assumed that all those concerned are citizens of a particular city-state or polis. They are, therefore, equals in the eyes of the law. This presumed equality is something ...